International Journal of Lightweight Materials and Manufacture最新文献

The current investigation aims to investigate the role of four major input parameters, i.e. Current (I), Gap Voltage (V), Pulse off time (T_off), and Pulse duration (T_on) on surface roughness (R_a) of Al–Mg-0.6Si-0.275Cu/SiC10 % hybrid composite samples fabricated by Stir-casting. In addition, paper focuses on the goal to ascertain the impact of distinct tool materials on surface morphology of Al/SiC composite. Further, mathematical models were developed using the L₂₉ orthogonal array in the Stat-Ease Modelling Expert V7.0 software. Thus, to validate the significance of the developed models, an Analysis of Variance was used. Finally, the topography of the specimen's surface (pre and post-machining) was performed using scanning electron microscopy (SEM). The results showed that at a peak current of 5 Amp, Gap voltage of 100V, Pulse on time of 100 μs, and Pulse off time of 40 μs, the lowest surface roughness with brass and copper electrodes was 0.29 μm and 0.32 μm obtained. The Brass electrode yielded 9.3 % lower surface roughness than the copper electrode.

One of the biggest problems the maritime industries confront is the erosion of composite structures brought on by interaction with sludge and sea debris. In the current study, erosion behaviour of cenosphere reinforced syntactic foam is examined in relation to specimen rotation angle, slurry concentration, and rotational speed. Moulding method was used to create the specimens. Sea sand particles were used as the erodent material in experiments carried out in a slurry pot erosion test rig. The impact of particular parameters on erosion is examined using the Taguchi L9 array. A scanning electron microscope was used to analyse the morphology of the eroded surfaces in order to analyse the erosion behaviour. Maximum erosion was seen when the Cenosphere content is least in the syntactic foams and the erosion process may be classified as semi-ductile in nature. It has been found that Cenosphere content have a major impact on erosion behaviour. The erosion damage in the matrix diminishes as the volume % of cenospheres rises, indicating that cenospheres boost the material's resistance against erosion.

As a promising solution to the growing demand for lightweighting, hot stamping has gained considerable applications in the automotive industry. Over the past few decades, the market for hot stamping has experienced explosive growth, with ongoing advancements offering potential for further expansion of its applications. This paper provides a historical overview of hot stamping alongside an in-depth analysis of future trends. Scientific publications, patents and industrial applications of hot stamping are systematically reviewed, with major developments in materials, processes, tools, and other relevant aspects being highlighted. Through data analysis, the current state of hot stamping is comprehensively depicted, and the trends in the development of hot stamping are revealed. Additionally, the future of extending hot stamping technologies to a broader range of materials is discussed, with suggestions furnished from both academic and industrial perspectives.

In recent year, Al–Mg₂Si composite becomes a topic to be discussed whether there is a potential to replace common automotive material, Al–Si in applications like piston and brake disk. However, the course with a sharp corner of primary Mg₂Si act as the stress concentration promote the initiation of crack to propagate, resulting in low mechanical and tribological performance. Hence, modification of Mg₂Si particles in Al–Mg₂Si composite is a prime concern. In the current work, the impact of cooling rates on the modification primary Mg₂Si crystal shape in 0.2 wt% Ba modified Al–20%Mg₂Si composite was evaluated. With mould preheating in different temperatures, the cooling rate was controlled. When the mould temperature is lowered, the cooling rate is increased which causes primary Mg₂Si crystal formation with different structures due to Ba atoms adsorption on {100} facets of Mg₂Si crystal which can be considered as external factors strengthening. Once the temperature of mould reduced from 600 °C to 400 °C, 200 °C and lastly to 25 °C, the primary Mg₂Si morphology changed from octahedral to truncated octahedral, truncated cube and finally to a cube respectively. Tensile results showed that Al–20%Mg₂Si-0.2%Ba composite solidified in the mould with temperature of 600 °C, the values of UTS and El% are higher than other composites solidified in other mould temperatures. Furthermore, the tensile fracture surface of Al–20%Mg₂Si-0.2%Ba composite solidified in the mould with temperature of 600 °C depicted less decohesion and debonding of the primary Mg₂Si particles in the aluminium matrix together with fine dimples on the fracture surface which elucidate the ductile fracture mechanism. The size and structure of the primary Mg₂Si in the Al–Mg₂Si composite can be regulated by using this practical, affordable approach, leading to the use of this composite in industrial products.

Biodegradable magnesium (Mg) alloys hold great potential for revolutionizing the field of biomedical engineering by offering temporary support during tissue healing and degrading without leaving permanent residues. However, their clinical applications have been limited due to their relatively high degradation rate. This study focuses on evaluating the in-vitro degradation, fatigue resistance, and fracture toughness properties of Mg alloys under cyclic loading conditions, mimicking real-life scenarios. Wire Electrical Discharge Machining (WEDM) was used to prepare spark-processed Mg samples with complex surface texture, and fine-polished Mg samples were used for comparison. The structural characterization, electrochemical corrosion behavior, degradation assessment, and mechanical integrity of the samples were comprehensively analysed. The results show that the Electrical Discharge processed (EDed) Mg sample exhibited uniformly distributed overlapped craters on the surface, which led to a lower charge transfer resistance and higher corrosion potential compared to the Pristine Mg sample. The rough surface topography and alkaline pH microenvironment of the EDed Mg sample facilitated rapid apatite mineralization, but the resulting Ca-deficient apatite compromised its structural stability. Both EDed and Pristine Mg samples exhibited a significant reduction in fatigue life and lower fracture toughness with prolonged immersion. These findings provide valuable insights into the performance of Mg alloys and their potential applications in biodegradable implants, guiding the design of robust implant materials for enhanced patient outcomes.

This work investigates the influence of parameters of initial ultrafine-grained (UFG) structure in commercially pure (CP) Al on annealing-induced hardening (AIH) and deformation-induced softening (DIS) effects. UFG structures were formed via processing CP Al by various methods of severe plastic deformation (high pressure torsion (HPT), equal channel angular pressing (ECAP) and combination of ECAP and cold rolling (CR)). AIH and DIS effects are observed in all the studied UFG structures. However, HPT Al demonstrates large increase of strength due to annealing and drastic gain of ductility after subsequent additional deformation whereas in ECAP Al and ECAP + CR Al both effects are much less pronounced. Microstructure characterization by X-ray diffraction (XRD) analysis, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) was performed for HPT Al and ECAP + CR Al in the three studied states: before and after annealing and after annealing and subsequent additional deformation. Analysis of microstructure evolution during annealing and subsequent additional deformation shows that the key microstructure parameter which is responsible for AIH and DIS effect is the change of dislocation density in grain interior in ECAP + CR Al, whereas in HPT Al the effects are related to the change of dislocation density at/near grain boundaries. In addition, outstanding combination of high strength (∼210 MPa), high electrical conductivity (∼62 %IACS) with sufficiently good ductility (7–10 %) and thermal stability (up to 150°С, at least) was achieved for ECAP + CR Al after annealing at 150 °C, 1h.

This study introduces a new rotary draw bending method that utilizes a variable curvature bending die. Unlike traditional methods that bend tubes with a fixed radius, this method gradually deforms the tube from a large to a small radius. The curvature of the bending die is determined by using an involute curve as the equation for the geometric location of the variable curvature. Hydroforming technology, utilizing fluid under pressure, replaces the mandrel in the rotational tensile bending process. The research was conducted using a thin-walled AA6063 tube with a 13.88 diameter-to-thickness ratio. The bending process was examined at critical bending ratios of 1 and 1.6 times the diameter, with a 90° bending angle. The maximum pressure that can be applied in any bend radius ratio was predicted using the necking criterion. The simulation and experimental tests analyzed the effects of internal fluid pressure and bend die curvature on defects such as wall thinning in the outer curvature of the bend, thickening of the wall in the inner curvature of the bend, and cross-section non-roundness. The results indicate that, at constant pressure, the amount of thinning and thickening of the bent tube is significantly improved when using the variable radius bending die compared to the fixed radius die.

The main objective of this investigation is to study the effect of post weld heat treatments (PWHTs) on tensile properties, hardness, and microstructure of pulsed CMT–MIG (cold metal transfer arc–metal inert gas) welded AA20214-T6 aluminum alloy joints. The welded joints were subjected to PWHT of artificial aging (AA), solution annealing treatment (ST) and ST + aging (STA). The tensile properties and microhardness of joints were evaluated. The microstructure of joints was studied using optical microscope (OM) and transmission electron microscope (TEM). The fractured surface of tensile specimens was analyzed using scanning electron microscope (SEM). Results showed that the tensile properties and hardness of as welded and PWHT joints are inferior compared to base metal (BM). This mainly refers to the microstructural heterogeneity in different regions of joints and softening of heat affected zone (HAZ) induced by the weld thermal cycle. The PWHTs of AA and ST did not show significant effect on tensile strength and hardness of AW joints. However, the slight reduction in elongation was observed in AA and ST joints. The STA joints showed higher joint efficiency of 71.6%, than other joints by compromising on the elongation. This refers to the greater precipitation of hardening precipitates in STA joints compared to AA and ST joints. It exhibited the higher tensile and yield strength of 326 MPa and 266 MPa and the lowest elongation of 3.8%. The STA joints showed 28.35%, 38.28% and 57.77% reduction in tensile strength, yield strength and elongation compared to BM respectively. All the tensile specimens of joints failed in HAZ owing to the lower hardness. This refers to dissolution of precipitates in HAZ. However, the HAZ softening is less severe in STA joints than AW, AA, and ST joints.

The effectiveness of local laser heat treatment technology to enhance the in situ formability of steels and aluminum alloys has already been widely acknowledged for the one-step forming of components with simple shape geometries. The present study demonstrates that this technology is also able to significantly improve the formability of a complex shaped multi-forming industrial part. An industrial grade advanced-high strength Dual-Phase DP1000 steel is used to analyze the multi-forming of a complex part to determine the most appropriate local laser heat treatment parameters and optimize in situ softening by correlating yield strength, ultimate tensile strength, elongation at fracture, strain hardening exponent and instantaneous strain hardening with local temperature dynamics during the laser treatment. Additionally, numerical simulation analysis using Autoform software is carried out to validate the selected heat affected zone and the in situ softening, ensuring that they are appropriate for improving the formability of the industrial part. These findings are then expanded to study the experimental forming of five in situ laser heat treated models, followed by comparative analysis with a benchmark. This study provides an insight and fundamental guidelines to perform in situ laser heat treatment on complex industrial parts leading to the production of the industrial multi-formed component with optimized formability.

Titanium alloys are widely used in various industrial applications due to their excellent properties. Due to its excellent heat conductivity and stability, graphene (Gn) can help Ti components last longer and experience less wear. In the current study, Ti6Al6V2Sn (Ti662) with various wt.% Gn was produced. The composite samples were subjected to metallurgical characterization to analyze the influence of Gn addition in the microstructure and phases formed. The properties such as microhardness and wear resistance were analyzed for all the samples. Variations in the load, sliding velocity, and distance were made during the wear test, and the effects of these factors on the wear rate and morphology of the worn surface were examined. Mechanical property analysis revealed that Ti662 + 0.5Gn exhibited the highest microhardness of 514.32HV, which was 1.45 times that of the matrix material. The sample with 0.5Gn exhibited increased wear resistance, the order of wear resistance observed was Ti662 + 0.5Gn > Ti662 + 0.75Gn > Ti662+1Gn > Ti662 + 0.25Gn > Ti662. The wear rate was reduced by 44.15 % at 40 N, 42.07 % and 52.02 % at 1.5 m/s and 2000 m for Ti662 + 0.5Gn composite. Worn surface morphology revealed that at elevated loads, abrasive and delamination wear was observed while at elevated velocity and distance, the formation of mechanically mixed layer (MML) was observed.